Why do animals become extinct?

When there are no more animals of a particular species left alive, that species is said to be
extinct.

In the distant past, several species of animals became extinct through natural causes. There might
have been a change in the climate of a particular region, and the plants or animals on which the
species lived could have died out because of the change in the weather. Or one animal might have been
destroyed by another that was stronger or faster.

But ever since human beings have been on Earth, and especially in the last hundred years, animal species
have become extinct because of hunting, pollution, or the destruction of the places where they live.

So many animals are now in danger of extinction that a list is kept in a Red Book. unfortunately, the
list gets longer every year.